Pierre Guillaume Frédéric Le Play

Le Play, Pierre Guillaume Frédéric (pyĕr gēyōmˈ frādārēkˈ lə plā) [key], 1806–82, French sociologist and economist. As an engineer he traveled through Europe, gathering data on the budgets of working-class families and making detailed studies to determine the relationships of the family and worker to the environment. His use of the social-survey method had a widespread influence on sociologists. Among his books are Les Ouvriers européens [the European workers] (1855), condensed and republished as Réforme sociale en France (1864), and La Constitution de l'Angleterre [the constitution of England] (1875).